WO2023171545A1 - Antenna unit and windowpane - Google Patents

Abstract

Provided are an antenna unit with excellent design properties, and a windowpane. An antenna unit (100) comprises a dielectric layer (10) that transmits visible light, a first conductor layer, a pseudo layer (60), and a second conductor layer that is spaced apart from the first conductor layer. The first conductor layer is provided to a first main surface side of the dielectric layer using the dielectric layer as a reference, and the second conductor layer is provided to the first main surface side or a second main surface side opposite to the first main surface of the dielectric layer using the dielectric layer (10) as a reference. In a plan view, at least part of the pseudo layer (60) is disposed around the second conductor layer. If n₁ and n₂ (where n₁ and n₂ are integers of 0 or more) respectively are gradation values of an N-th level (where N is a natural number) when read at a resolution of 400 dpi of a first region of the pseudo layer (60) that does not overlap with the second conductor layer and a second region of the second conductor layer that does not overlap with the pseudo layer (60) in a plan view, then ｜n₁-n₂｜/N≦1.09×10^-1.

Description

Antenna unit and window glass

The present invention relates to an antenna unit and window glass.

An antenna unit that includes a mesh antenna conductor and a mesh ground conductor that is used for window glass of buildings, automobiles, etc. is known (for example, Patent Document 1).

International Publication No. 2020/095786

Here, since the mesh pattern of the antenna conductor and the ground conductor described in Patent Document 1 mentioned above is formed on a portion of the board, the mesh pattern is easily noticeable when the board is visually recognized. Therefore, there is a need for an antenna unit with an inconspicuous pattern and improved design.

In view of the above-mentioned problems, the present invention aims to provide an antenna unit and window glass with excellent design.

One aspect of the present invention provides an antenna unit having the following configurations [1] to [13].
[1] A dielectric layer through which visible light passes;
a first conductor layer;
a pseudo layer;
a second conductor layer provided apart from the first conductor layer;
Equipped with
The first conductor layer is provided on the first main surface side of the dielectric layer with respect to the dielectric layer,
The second conductor layer is provided on a side of the first main surface of the dielectric layer or a second main surface opposite to the first main surface of the dielectric layer, with the dielectric layer as a reference,
In plan view, at least a portion of the pseudo layer is arranged around the second conductor layer,
In the planar view, each of a first region of the pseudo layer that does not overlap with the second conductor layer and a second region of the second conductor layer that does not overlap with the pseudo layer is determined at a resolution of 400 dpi. Assuming that the gradation values of N (N is a natural number) stages when read are n ₁ and n ₂ (n ₁ and n ₂ are integers of 0 or more),
|n ₁ -n ₂ |/N≦1.09×10 ⁻¹ Antenna unit.
[2] The antenna unit according to [1], wherein |n ₁ -n ₂ |/N≦6.25×10 ⁻² .
[3] The antenna unit according to [1] or [2], wherein N=256 and n ₂ ≦246.
[4] The first conductor layer includes a radiation conductor,
The second conductor layer includes a ground conductor,
The antenna unit according to any one of [1] to [3], wherein the second conductor layer is provided on the second main surface side of the dielectric layer with respect to the dielectric layer.
[5] The first conductor layer includes a radiation conductor,
The second conductor layer includes a ground conductor,
The antenna unit according to any one of [1] to [3], wherein the second conductor layer is provided on the first main surface side of the dielectric layer with respect to the dielectric layer.
[6] The first conductor layer includes a ground conductor,
The second conductor layer includes a radiating conductor,
The antenna unit according to any one of [1] to [3], wherein the second conductor layer is provided on the second main surface side of the dielectric layer with respect to the dielectric layer.
[7] The first conductor layer includes a radiation conductor,
The second conductor layer includes a waveguide element that guides radio waves radiated by the radiation conductor in a predetermined direction,
The second conductor layer is provided on the second main surface side of the dielectric layer with respect to the dielectric layer,
The antenna unit according to any one of [1] to [3], further including a ground conductor layer provided on the opposite side of the dielectric layer with respect to the first conductor layer.
[8] The antenna unit according to any one of [1] to [7], wherein the pseudo layer includes a pattern in which array elements are arranged spaced apart from each other.
[9] The antenna unit according to [8], wherein the array element has a conductivity of 1×10 ⁶ (S/m) or more.
[10] The shape of the array element is circular,
The antenna unit according to [9], wherein the average diameter of the array element is λ ₀ /2 or less, where λ ₀ is the free space wavelength of radio waves transmitted and received by the antenna unit.
[11] The shape of the array element is rectangular,
[12] The pseudo layer of the antenna unit according to [9], wherein the length of the long side of the array element is λ ₀ /2 or less, where λ ₀ is the free space wavelength of radio waves transmitted and received by the antenna unit. is composed of an insulator,
The antenna unit according to any one of [1] to [7], wherein the insulator has a conductivity of less than 1×10 ⁶ (S/m).
[13] The antenna unit according to any one of [1] to [12], wherein the second conductor layer includes a mesh conductor pattern.

One aspect of the present invention provides a window glass including an antenna unit having the configuration of any one of [1] to [13].

According to one aspect of the present invention, it is possible to provide an antenna unit and window glass with excellent design.

FIG. 3 is a top view of the window glass according to the first embodiment. FIG. 2 is a top view of the antenna unit according to the first embodiment. FIG. 2 is a plan view of the antenna unit according to the first embodiment. FIG. 3 is a plan view showing a radiating element layer, a ground conductor layer, and a pseudo layer formed on a dielectric layer of the antenna unit according to the first embodiment. FIG. 3 is an enlarged plan view of a boundary area A1 according to the first embodiment. FIG. 3 is a diagram for explaining an example of homogenization processing according to the first embodiment. FIG. 3 is a diagram for explaining an example of homogenization processing according to the first embodiment. FIG. 7 is a top view of the antenna unit according to Configuration Example 1 of Embodiment 2; FIG. 7 is a plan view showing a radiating element layer, a ground conductor layer, and a pseudo layer formed in a dielectric layer of an antenna unit according to Configuration Example 1 of Embodiment 2; FIG. 7 is a plan view showing a radiating element layer, a ground conductor layer, and a pseudo layer formed in a dielectric layer of an antenna unit according to Configuration Example 2 of Embodiment 2; FIG. 7 is a top view of an antenna unit according to configuration example 3 of embodiment 2; FIG. 7 is a cross-sectional view of an antenna unit according to a third embodiment. FIG. 7 is a plan view of an antenna unit according to a third embodiment. FIG. 7 is a plan view showing a radiating element layer, a waveguide layer, and a pseudo layer formed in a dielectric layer of an antenna unit according to a third embodiment. FIG. 7 is a cross-sectional view of a modification of the antenna unit according to Embodiment 3. FIG. 7 is a top view of an antenna unit according to a fourth embodiment. FIG. 7 is a plan view of an antenna unit according to a fifth embodiment. FIG. 7 is a cross-sectional view of an antenna unit according to a fifth embodiment. FIG. 7 is a cross-sectional view of an antenna unit according to a fifth embodiment. FIG. 3 is a diagram showing the relationship between (dot diameter/dot pitch) and gradation value. FIG. 3 is a diagram showing the relationship between (line width of mesh/pitch of mesh) and gradation value.

Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. In each drawing, the same elements are denoted by the same reference numerals, and redundant explanation will be omitted as necessary. In each embodiment, deviations in parallel, horizontal, vertical, etc. directions are allowed to an extent that does not impair the effects of the present invention. Moreover, the X-axis direction, the Y-axis direction, and the Z-axis direction are a direction parallel to the X-axis, a direction parallel to the Y-axis, and a direction parallel to the Z-axis, respectively. The X-axis direction, Y-axis direction, and Z-axis direction are orthogonal to each other. The XY plane, YZ plane, and ZX plane are, respectively, a plane parallel to the X-axis direction and the Y-axis direction, a plane parallel to the Y-axis direction and the Z-axis direction, and a plane parallel to the Z-axis direction and the X-axis direction. .

"Plan view" and "plan view" in this embodiment refer to viewing the XY plane or the XY plane itself, respectively. Furthermore, "top view" and "top view" in this embodiment refer to viewing the ZX plane or the ZX plane itself, respectively.

In this embodiment, the term "same plane" allows deviations to the extent that the effects of the present invention are not impaired.

The "antenna unit" in this embodiment is used to propagate signals in a predetermined frequency band. Hereinafter, the predetermined frequency band may be referred to as a target frequency band. The target frequency band may be from 4G LTE (Long Term Evolution) to 5G frequency band, for example, may be a frequency band from 700 MHz to 6 GHz (so-called sub6), but is not limited to these. That is, the target frequency band may be a frequency band below 700 MHz, a frequency band above 6 GHz, for example, a 28 GHz band, or a frequency band above 30 GHz called millimeter waves, such as a 79 GHz band. The antenna unit may be used, for example, in wireless communication standards such as 5G and Bluetooth (registered trademark), and wireless LAN (Local Area Network) standards such as IEEE802.11ac. Furthermore, when used in a vehicle, the antenna unit may be used in an on-vehicle radar system, a V2X communication system, or a dedicated narrowband communication system called DSRC (Dedicated Short Range Communications). Furthermore, the antenna unit may be compatible with standards other than these.

<Overview of embodiment>
First, an overview of the embodiment described later will be explained. The antenna unit according to this embodiment includes a dielectric layer through which visible light passes, a first conductor layer, a pseudo layer, and a second conductor layer.

The first conductor layer is a layer provided on the first main surface side of the dielectric layer with respect to the dielectric layer.
The second conductor layer is a layer provided apart from the first conductor layer by a predetermined distance when viewed from above. The second conductor layer is provided on the first main surface side or the second main surface side of the dielectric layer with the dielectric layer as a reference. The second main surface is a main surface of the dielectric layer that is opposite to the first main surface.

At least a portion of the pseudo layer is arranged around the second conductor layer in plan view.
Here, in a plan view, a region of the pseudo layer where the pseudo layer exists without overlapping with the second conductor layer is defined as a first region. Further, a region of the second conductor layer where the second conductor layer exists without overlapping with the pseudo layer is defined as a second region. Then, when both the first area and the second area are read at a resolution of 400 dpi, the N-level gradation values of the first area and the second area are set as n ₁ and n ₂ , respectively. However, N is a natural number, and n ₁ and n ₂ are integers of 0 or more. At this time, the value obtained by normalizing the absolute value of the difference in gradation values, that is, |n ₁ -n ₂ |/N is 0 or more and 1.09×10 ⁻¹ or less.

According to the antenna unit according to the present embodiment, at least a part of the pseudo layer is arranged around the second conductor layer, and the difference in gradation value between the first region and the second region is small, so that the second conductor layer is arranged around the second conductor layer. The pseudo layer makes it less noticeable. Therefore, the design quality can be improved.

The antenna unit will be specifically explained in Embodiments 1 to 5 below.

<Embodiment 1>
First, Embodiment 1 of the present invention will be described. FIG. 1 is a top view of a window glass 1 according to a first embodiment. The window glass 1 is a window glass attached to a building or a vehicle. The window glass 1 includes a window glass main body 200, an antenna unit 100, and support parts 300a and 300b.

The window glass body 200 is a transparent plate-like member through which visible light passes. In FIG. 1, the main surface of the window glass body 200 is parallel to the XY plane, and the thickness direction is parallel to the Z-axis direction. Note that the positive direction of the Z-axis is the indoor side, and the negative direction of the Z-axis is the outdoor side. The window glass body 200 is a dielectric member whose main component is dielectric. The material of the window glass body 200 is glass, but may also be resin.

The antenna unit 100 is a plate-shaped, sheet-shaped, or film-shaped member provided on the main surface of the window glass body 200 on the indoor side via supporting parts 300a and 300b. In this figure, the antenna unit 100 is provided along the main surface of the window glass body 200. The antenna unit 100 transmits and receives radio waves in a target frequency band. The antenna unit 100 is a planar antenna, such as a patch antenna, a microstrip antenna, or a slot antenna.

The support parts 300a and 300b are members that support the antenna unit 100 with respect to the window glass main body 200. The support parts 300a and 300b support the antenna unit 100 so that a space is formed between the window glass main body 200 and the antenna unit 100. Note that the support parts 300a and 300b may support the antenna unit 100 so that the window glass main body 200 is in contact with the main surface of the antenna unit 100, but in order to reduce the risk of thermal cracking, it is preferable to support the antenna unit 100 as shown in FIG. Support so that a space is formed between the In this case, the support parts 300a and 300b may be spacers for securing a space between the window glass main body 200 and the antenna unit 100, or may be a casing of the antenna unit 100.
The material of the supports 300a, 300b may be dielectric. For example, the material of the support parts 300a and 300b may be a resin such as silicone resin, polysulfide resin, or acrylic resin. Further, the material of the support parts 300a and 300b may be metal such as aluminum.

FIG. 2 is a top view of the antenna unit 100 according to the first embodiment. FIG. 3 is a plan view of the antenna unit 100 according to the first embodiment. FIG. 3 shows the XY plane when viewed from the Z-axis negative direction side. The antenna unit 100 includes a dielectric layer 10, a radiating element layer 20, a pseudo layer 60, and a ground conductor layer as examples of the dielectric layer, first conductor layer, pseudo layer, and second conductor layer described in the overview. 40. Further, FIG. 4 is a plan view showing the radiating element layer 20, the ground conductor layer 40, and the pseudo layer 60 formed on the dielectric layer 10 of the antenna unit 100 according to the first embodiment. FIG. 4 shows a plan view seen from the first main surface side and a plan view seen from the second main surface side.

As shown in FIG. 2, the dielectric layer 10 is a transparent plate-like, sheet-like, or film-like member through which visible light passes. The dielectric layer 10 has a dielectric as a main component. The material of the dielectric layer 10 may be glass, ceramics, or resin. Examples of the dielectric layer 10 include a glass substrate, acrylic, polycarbonate, PVB (polyvinyl butyral), COP (cycloolefin polymer), PET (polyethylene terephthalate), polyimide, ceramics, or sapphire. When the dielectric layer 10 is a glass substrate, examples of the material include alkali-free glass, quartz glass, soda lime glass, borosilicate glass, alkali borosilicate glass, or aluminosilicate glass.

The visible light transmittance of the dielectric layer 10 is preferably 30% or more, more preferably 50% or more, even more preferably 70% or more, particularly preferably 80% or more, and most preferably 90% or more. The visible light transmittance is measured in accordance with JIS R 3106 (1998).

The dielectric layer 10 has a main surface parallel to the XY plane like the window glass main body 200, and a thickness direction parallel to the Z axis. Hereinafter, the main surface of the dielectric layer 10 on the negative side of the Z-axis will be referred to as a first main surface 10(1), and the main surface of the dielectric layer 10 on the positive side of the Z-axis will be referred to as a second main surface 10(2). There are cases where this happens.
That is, the second main surface 10(2) is a main surface opposite to the first main surface 10(1).

The radiating element layer 20 is a layer that includes a radiating conductor that is formed to be able to transmit and receive radio waves in the target frequency band described above. The radiating element layer 20 is provided on the first main surface 10(1) side of the dielectric layer 10 with the dielectric layer 10 as a reference, that is, on the negative Z-axis side with the dielectric layer 10 as a reference. In the first embodiment, the radiating element layer 20 is specifically formed on at least a part of the first main surface 10(1) of the dielectric layer 10 so that its surface is parallel to the XY plane. is formed.

The ground conductor layer 40 is a layer containing a ground conductor that forms a ground plane. The ground conductor layer 40 is provided corresponding to the radiating element layer 20. Since the ground conductor layer 40 may be visually noticeable, in the first embodiment, the ground conductor layer 40 is camouflaged to make it less noticeable. In the first embodiment, the ground conductor layer 40 is arranged on the second main surface 10(2) side of the dielectric layer 10 with the dielectric layer 10 as a reference, that is, on the positive Z-axis side with the dielectric layer 10 as a reference. provided. Specifically, the ground conductor layer 40 is formed on at least a portion of the second main surface 10(2) of the dielectric layer 10 so that its surface is parallel to the XY plane.

The pseudo layer 60 is a camouflage layer formed to make the ground conductor layer 40 less noticeable. Similar to the ground conductor layer 40, the pseudo layer 60 is provided on the second main surface 10(2) side of the dielectric layer 10 with the dielectric layer 10 as a reference. More specifically, pseudo layer 60 is formed on the same plane as ground conductor layer 40 . That is, the pseudo layer 60 is formed on at least a part of the second main surface 10(2) of the dielectric layer 10 so that its surface is parallel to the XY plane.

3 and 4 show, as an example, a configuration in which two antenna elements 20a and 20b are formed in the radiation element layer 20 shown in FIG. 2 (see the first main surface side in FIG. 4). Further, a configuration is shown in which two ground conductors 40a and 40b are formed on the ground conductor layer 40 shown in FIG. 2 (see the second main surface side in FIG. 4). Ground conductors 40a and 40b are provided corresponding to antenna elements 20a and 20b, respectively. The antenna element 20a and the ground conductor 40a and the antenna element 20b and the ground conductor 40b are arranged apart from each other by a predetermined distance in the X-axis direction. Note that the number of antenna elements and ground conductors included in the antenna unit 100 is not limited to two, but may be one, or may be three or more.

[Antenna element 20a]
Below, details of the antenna element 20a will be explained. Note that the antenna element 20b is the same as the antenna element 20a, so a description thereof will be omitted.

The antenna element 20a is a planar conductor pattern formed on the first main surface 10(1) side. Examples of the conductor material used for the antenna element 20a include gold, silver, copper, platinum, aluminum, and chromium. The antenna element 20a may be formed by plating the above-mentioned material. By plating, it is possible to form the antenna element 20a which is resistant to corrosion and has a good design. Further, the antenna element 20a may be formed by sintering a pattern formed by screen printing a paste of silver, copper, or the like on the first main surface 10(1).

The antenna element 20a may be formed directly on the first main surface 10(1), or may be formed indirectly. For example, the antenna element 20a may be formed on the first main surface 10(1) of the dielectric layer 10 with a resin layer interposed therebetween. For the resin layer, for example, an intermediate film such as polyvinyl butyral or ethylene vinyl acetate, polyethylene terephthalate, or optically transparent adhesive (OCA) can be used.

The antenna element 20a has a radiation conductor 21a and a feed line 30a.

The radiation conductor 21a includes at least one patch conductor. In the first embodiment, the radiation conductor 21a includes four patch conductors 22a, 23a, 24a, and 25a. Patch conductors 22a, 23a, 24a, and 25a may be composed of solid planar conductors. However, the present invention is not limited thereto, and the patch conductors 22a, 23a, 24a, and 25a may be configured with a mesh-like conductor pattern formed so that gaps are formed in a plan view. In this case, the field of view can be secured and the design can be improved.

The power supply line 30a is a conductor pattern formed on the first main surface 10(1) side. The power supply line 30a functions as a signal wiring. In the first embodiment, the power supply line 30a is a strip conductor extending in the Y-axis direction. The power supply line 30a may be composed of a solid planar conductor. However, the present invention is not limited thereto, and the power supply line 30a may be configured with a mesh-like conductor pattern formed so that gaps are formed in a plan view. In this case, the field of view can be secured and the design can be improved.

In the first embodiment, the power supply line 30a is formed integrally with the radiation conductor 21a. The feed line 30a is connected to the radiation conductor 21a at one end 32a. More specifically, the power supply line 30a has a branch path to the patch conductors 22a, 23a, a branch path to the patch conductor 24a, and the patch conductor 25a, and these branch paths are connected to each other at one end 32a. It has a branch point 36a. Further, the power supply line 30a is connected to a wireless device such as a transmitter at the other end 33a. The end 33a of the power supply line 30a functions as a power supply end. Note that in the first embodiment, the end portion 33a coincides with the end portion of the dielectric layer 10 in the Y-axis positive direction, but it is previously aligned in the Y-axis negative direction from the end portion of the dielectric layer 10 in the Y-axis positive direction. They may be separated by a predetermined distance.

[Grounding conductor 40a]
Below, details of the ground conductor 40a will be explained. Note that since the ground conductor 40b is similar to the ground conductor 40a, the description thereof will be omitted.

The ground conductor 40a is a planar conductor pattern formed on the second main surface 10(2) side.

Examples of the conductor material used for the ground conductor 40a include gold, silver, copper, platinum, aluminum, and chromium. The ground conductor 40a may be formed by plating the above-mentioned material. By plating, it is possible to form a ground conductor 40a that is resistant to corrosion and has a good design. Further, the ground conductor 40a may be formed by sintering a pattern formed by screen printing a paste such as silver or copper on the second main surface 10(2).

The ground conductor 40a may be formed directly on the second main surface 10(2), or may be formed indirectly. For example, the ground conductor 40a may be formed on the second main surface 10(2) of the dielectric layer 10 via a resin layer. For the resin layer, for example, an interlayer film of polyvinyl butyral or ethylene vinyl acetate, polyethylene terephthalate, OCA, or the like can be used.

The ground conductor 40a includes a linear ground conductor 41a formed so as to create a gap in plan view, and a planar ground conductor 50a connected to the linear ground conductor 41a.

The linear ground conductor 41a is a continuous pattern, specifically a mesh-like conductor pattern, in which linear conductors are electrically connected to each other. In other words, the area where the linear ground conductor 41a is formed includes a grid-like gap when viewed from above. This secures the field of view and improves the design. The linear ground conductor 41a exists on the second main surface 10(2) side so that at least a portion thereof overlaps the antenna element 20a in a plan view. For example, in the first embodiment, the linear ground conductor 41a is formed in a rectangular area. However, the shape of the region where the linear ground conductor 41a is formed is not limited to this, and may be other polygonal or circular shapes. In the first embodiment, the end of the linear ground conductor 41a in the Y-axis positive direction coincides with the end of the dielectric layer 10 in the Y-axis positive direction. may be spaced apart by a predetermined distance from the end of the Y-axis in the negative direction of the Y-axis.

As an example, the angle between the linear conductors of the linear ground conductor 41a is approximately 90°, but is not limited to this, and may be an acute angle or an obtuse angle. That is, the mesh may be rectangular or diamond-shaped. When the mesh is rectangular, it is preferably square from the viewpoint of design. The mesh may also have other polygonal shapes, such as hexagonal shapes. When the mesh is hexagonal, a regular hexagonal shape is preferred from the viewpoint of design. The mesh may also have a random shape created by a self-organization method.

The planar ground conductor 50a is a ground electrode corresponding to the end portion 33a that functions as a power feeding end. Specifically, the planar ground conductor 50a is formed on the second main surface 10(2) side at a position overlapping the end portion 33a in plan view. In Embodiment 1, the planar ground conductor 50a is formed at the end of the dielectric layer 10 in the positive Y-axis direction. They may be formed at positions separated by a predetermined distance. The planar ground conductor 50a is formed in a solid pattern.

[Pseudo layer 60]
In plan view, the pseudo layer 60 is arranged around the region where the ground conductor 40a is formed, without overlapping the region where the ground conductor 40a is formed. "Disposed around" indicates that the ground conductor 40a is disposed so as to be in contact with at least a portion of the outer edge of the region where the ground conductor 40a is formed in a plan view. For example, when the region where the ground conductor 40a is formed is rectangular, the pseudo layer 60 is arranged so as to be in contact with and surround the three sides of the rectangle excluding the end edge in the Y-axis positive direction, as shown in FIG. It's fine. However, the present invention is not limited thereto, and the pseudo layer 60 may be arranged so as to be in contact with and surround all four sides of the rectangle. Alternatively, the pseudo layer 60 may be arranged so as to be in contact with one side or two sides of the rectangle. Note that "contacting" may mean direct contact, but there may be a gap that does not impair the effect. If the gap is large, the boundary between the pseudo layer 60 and the ground conductor 40a becomes noticeable.

Here, it is preferable that the pseudo layer 60 does not affect the antenna performance, but the size of the gap may affect the antenna performance. For example, as shown in FIGS. 2 to 4, when the pseudo layer 60 is formed on the same plane as the ground conductor 40a and is made of a conductor, the antenna performance changes depending on the size of the gap. In this case, when a gap exists, the gap may be 20 μm or more and 300 μm or less. If the gap is 20 μm or more, the influence of the pseudo layer 60 on antenna performance will be small. Further, if the gap is 300 μm or less, the boundary between the pseudo layer 60 and the ground conductor 40a becomes less noticeable. As an example, the gap is 30 μm.

On the other hand, if the pseudo layer 60 is formed on a different plane from the ground conductor 40a, or if the pseudo layer 60 is made of an insulator, the effect on antenna performance is sufficiently small regardless of the size of the gap. . Therefore, in this case, when a gap exists, the gap may be more than 0 μm and not more than 300 μm.

Note that a conductor is a conductive material with a conductivity σ of 1×10 ⁶ (S/m) or more, and an insulator is a dielectric material with a conductivity σ of less than 1×10 ⁶ (S/m). It is.

In FIGS. 3 and 4, the ground conductor layer 40 includes ground conductors 40a and 40b spaced apart from each other in the X-axis direction, and the pseudo layer 60 is also arranged around the ground conductor 40b in plan view. For example, the pseudo layer 60 may be arranged around the plurality of ground conductors 40a, 40b so as to integrally connect the plurality of ground conductors 40a, 40b in plan view.

By arranging at least a portion of the pseudo layer 60 around the ground conductor layer 40 in plan view in this way, the ground conductor layer 40 can be camouflaged. This improves the design. As shown in FIGS. 3 and 4, when the ground conductor layer 40 of the antenna unit 100 is formed with a plurality of ground conductors 40a, 40b separated from each other, the plurality of ground conductors 40a, 40b are integrated. It has a particularly remarkable effect because it looks like an object.

In addition, in FIGS. 3 and 4, the shape of the pseudo layer 60 is designed to be a rectangular area as a whole together with the area where the ground conductor layer 40 is formed, but the shape is not limited to this, and may be circular or It may also be designed to have other shapes. For example, the shape of the pseudo layer 60 may be designed to have an arbitrary pattern together with the area where the ground conductor layer 40 is formed. Thereby, the design quality can be further improved.

Note that the end of the pseudo layer 60 in the X-axis direction may coincide with the end of the dielectric layer 10 in the X-axis direction; They may be separated by a distance. The same applies to the ends in the Y-axis direction.

FIG. 5 is an enlarged plan view of area A1 according to the first embodiment. The region A1 is a region including the boundary between the pseudo layer 60 and the ground conductor layer 40, as shown in FIGS. 3 and 4.

It is preferable that the pseudo layer 60 has a structure in which scattering by radio waves is sufficiently small and does not affect antenna performance. The pseudo layer 60 may be formed of a conductor or an insulator. If the pseudo layer 60 is an insulator, the scattering of radio waves by the pseudo layer 60 can be sufficiently reduced, and the influence on antenna characteristics can be reduced. Furthermore, when the pseudo layer 60 is composed of a conductor, scattering of radio waves by the pseudo layer 60 can be reduced by making the conductors spatially separated, that is, composed of a plurality of conductors that are not electrically conductive. The effect on antenna characteristics can be reduced.

In the first embodiment, the pseudo layer 60 includes a pattern in which conductor array elements 61 are arranged at a predetermined pitch and spaced apart from each other. In FIG. 5, the array element 61 is circular and may be called a dot. It is preferable that the diameter of the array element 61 is λ ₀ /2 or less because scattering caused by radio waves can be reduced. The diameter of the array element 61 is more preferably λ ₀ /5 or less, and even more preferably λ ₀ /10 or less. As shown in FIG. 5, the array element 61 may be arranged at a position where a predetermined gap is created between the array element 61 and the ground conductor layer 40 in a plan view. As an example, the distance from the outer edge of the ground conductor layer 40 to the array element 61 is 30 μm.

Note that the array element 61 may have a rectangular shape. When the shape of the array element 61 is rectangular, it is preferable that the length of one side, especially the length of the long side, be λ ₀ /2 or less because scattering by radio waves can be reduced. The length of one side of the rectangle, particularly the length of the long side, is more preferably λ ₀ /5 or less, and even more preferably λ ₀ /10 or less. Here, λ ₀ is the wavelength of radio waves transmitted and received by the antenna unit 100 in free space. Furthermore, the term "rectangle" includes not only rectangles and squares, but also shapes with chamfered corners of rectangles and squares.

Further, the shape of the array element 61 may be a rhombus, a triangle, a hexagon, another polygon, a star, or other shapes.

Examples of the conductor material used for the array element 61 include gold, silver, copper, platinum, aluminum, or chromium. From the viewpoint of manufacturing cost, the material of the conductor used for the array element 61 is preferably the same material as the second conductor layer described in the overview, that is, the same material as the ground conductor layer 40 in the first embodiment. The pseudo layer 60 may be formed by plating the above-mentioned material. By plating, it is possible to form a pseudo layer 60 that is resistant to corrosion and has a good design. Further, the pseudo layer 60 may be formed by sintering a pattern formed by screen printing a paste of silver, copper, or the like on the second main surface 10(2).

The pseudo layer 60 may be formed directly on the second main surface 10(2), or may be formed indirectly. For example, the pseudo layer 60 may be formed on the second main surface 10(2) side of the dielectric layer 10 via a resin layer. For the resin layer, for example, an intermediate film such as polyvinyl butyral or ethylene vinyl acetate, polyethylene terephthalate, or an optically transparent adhesive can be used.

Here, in plan view, the region where the pseudo layer 60 exists without overlapping with the ground conductor layer 40, which is the second conductor layer, is defined as a first region. Further, a region where the ground conductor layer 40, which is the second conductor layer, exists without overlapping with the pseudo layer 60 is defined as a second region. In the first embodiment, since the pseudo layer 60 and the ground conductor layer 40 do not overlap in plan view, the first region is an arbitrary region of the pseudo layer 60, and the second region is an arbitrary region of the ground conductor layer 40. It is.

[Difference index F and inconspicuousness]
If the patterns included in the first area and the second area are minute, or if a person views the first area and the second area from a distance, the first area and the second area will be homogenized from the human eye. It looks like a solid color. This phenomenon occurs particularly when the resolution of the human eye is lower than the resolution at which the patterns included in the first and second regions can be recognized. The density of color visible to the human eye changes depending on the diameter, line width, or pitch of the pattern. For example, the larger the diameter of the dots, the larger the line width, or the smaller the pitch, the darker the color of the area appears. Further, for example, the smaller the diameter of the dots, the smaller the line width, or the larger the pitch, the lighter the color of the area appears.

In the first embodiment, the above-mentioned phenomenon is utilized to reduce the difference in shading between the color of the first area when homogenized and the color of the second area when homogenized. As a result, the first area and the second area appear continuous and integrated to the human eye, making the second area less noticeable.

(Calculation method of gradation difference index F)
In the first embodiment, as an index of the difference in shading, N (N is a natural number) gradations between the first area and the second area when both the first area and the second area are read at a resolution of 400 dpi. A value F obtained by normalizing the difference in values by the number of gradations is used. F is expressed by the following formula (1).
F=|n ₁ -n ₂ |/N...(1)
n ₁ is the gradation value of the first area, and n ₂ is the gradation value of the second area.

In this way, the gradation difference index F can be obtained by substituting the gradation value n ₁ of the first region and the gradation value n ₂ of the second region into equation (1).

The above-mentioned gradation difference index F is preferably 0 or more and 1.09×10 ⁻¹ or less, more preferably 0 or more and 6.25×10 ⁻² or less, even more preferably 0 or more and 3.52×10 ⁻² or less, and 0 or more. Particularly preferred is 1.56×10 ⁻² or less. When F is 0 or more and 1.09×10 ⁻¹ or less, the difference in shading becomes small and the second region becomes less noticeable. Further, when F is 0 or more and 6.25×10 ⁻² or less, the difference in shading becomes smaller and the second region becomes less noticeable. Furthermore, when F is 0 or more and 3.52×10 ⁻² or less, the difference in shading becomes even smaller, making the second region even less noticeable. Further, when F is 0 or more and 1.56×10 ⁻² or less, the difference in shading becomes so small that the boundary is not visible, making the second region particularly difficult to stand out. Here, the shade difference index F is a value when the resolution of the imaging unit is 400 dpi.
In addition, when N=256, |n ₁ -n ₂ | is preferably 0 or more and 28 or less, more preferably 0 or more and 16 or less, even more preferably 0 or more and 9 or less, and particularly preferably 0 or more and 4 or less.

(Calculation method of tone values n ₁ and n ₂ )
The gradation value n ₁ of the first area and the gradation value n ₂ of the second area can be calculated from an image obtained by homogenizing the patterns included in each of the first area and the second area.
6A and 6B are diagrams for explaining an example of the homogenization process according to the first embodiment. On the left side of FIG. 6A, the dot pattern of the first region included in the pseudo layer 60 is shown. First, a dot pattern in a first area is photographed using an imaging section set to a predetermined resolution. As the imaging section, an imaging section included in an optical reading device such as a digital camera or a scanner may be used. In this case, by setting the resolution of the imaging unit to be equal to or lower than the resolution of the human eye, the captured image shown on the right side of FIG. 6A can be obtained. The resolution here indicates relative resolution. The captured image includes a homogenized pattern 70 that is a homogenized image area. Then, by measuring the gradation value of the homogenized pattern 70, the gradation value _n1 of the first region can be obtained. The measurement of gradation values can be performed using any image processing software. The gradation value n ₁ may be the gradation value of one point in the homogenization pattern 70, or may be the average of the gradation values of multiple points in the homogenization pattern 70.

The resolution of the imaging unit is preferably 100 dpi or more and 500 dpi or less, more preferably 200 dpi or more and 400 dpi or less, and even more preferably 300 dpi or more and 400 dpi or less. When the resolution of the imaging unit is 100 dpi or more, the difference in patterns is reflected in the gradation values, so the reliability of the gradation values is improved. Further, when the resolution of the imaging unit is 200 dpi or more, the reliability of the gradation values is further improved because differences in gradation values become noticeable depending on the pattern. Further, when the resolution of the imaging unit is 300 dpi or more, a photographed image equivalent to that of the human eye can be obtained, so that gradation values can be calculated in accordance with the actual situation. Further, when the resolution of the imaging unit is 700 dpi or less, a captured image with less unevenness can be obtained, so that gradation values can be calculated. Further, when the resolution of the imaging unit is 600 dpi or less, a captured image with less unevenness can be obtained, so that the accuracy of calculating gradation values is improved. Note that the resolution of the human eye is said to be 300 dpi or less, or 400 dpi or less.

On the left side of FIG. 6B, the mesh pattern of the second region included in the ground conductor layer 40 is shown. A homogenized pattern 72 can be obtained by performing homogenization processing on the mesh pattern in the second region in the same manner as the dot pattern on the pseudo layer 60. Then, by measuring the gradation value of the homogenized pattern 72, the gradation value _n2 of the second region can be obtained.

In addition, as another method of homogenization processing, the dot pattern of the first area included in the pseudo layer 60 is photographed using an imaging section set to a predetermined resolution, and the captured image obtained by photographing is The homogenized pattern 70 may be obtained by performing image processing. Then, by measuring the gradation value of the homogenized pattern 70, the gradation value _n1 of the first region can be obtained. The measurement of gradation values can be performed using any image processing software. As the imaging section in this case, an imaging section included in an optical reading device such as an optical microscope, a digital camera, or a scanner may be used. The resolution of the imaging unit in this case may be higher than the resolution that allows the pattern to be recognized.
Further, the gradation value _n2 of the second area may take into consideration the gradation value near the boundary with the first area, and may increase or decrease as the distance from the first area increases.

[Pattern dimensions and tone values]
Here, the dimensions of the pattern are closely related to the tone values when the pattern is observed.

For example, if a grayscale value (N=256) is used as an example of a gradation value, the relationship between (dot diameter/dot pitch) in the first area and the gradation value _n1 of the first area is (dot diameter/dot pitch). The dot pitch) may be expressed by the following equation, where _x1 is the dot pitch.
n ₁ = -261.40x ₁ +321.02...(2)

For example, when a gray scale value (N=256) is used as an example of a gradation value, the relationship between (mesh line width/mesh pitch) in the second area and the gradation value _n2 of the second area is as follows. It may be expressed by the following formula, where (mesh line width/mesh pitch) is set as _x2 .
n ₂ = -861.64x ₂ +250.71...(3)

[Gradation value and antenna performance]
When the line width of the mesh in the second region is small or the pitch of the mesh is large, radio waves are more likely to pass through, resulting in a decrease in antenna performance. On the other hand, when the line width of the mesh in the second region is large or the pitch of the mesh is small, it becomes difficult for radio waves to pass through, so that the antenna performance improves. Here, as mentioned above, (mesh line width/mesh pitch) x ₂ has a correlation with the gradation value n ₂ of the second area, so the antenna performance also changes depending on the gradation value n ₂ of the second area. . Specifically, the larger the gray scale value n ₂ of the second region is, the lower the antenna performance is, and the smaller the gray scale value n ₂ of the second region is, the better the antenna performance is.

For example, when a gray scale value (N=256) is used as an example of a gradation value, in order to improve antenna performance, _n2 is preferably 246 or less, more preferably 240 or less, even more preferably 232 or less, and 217 The following is particularly preferable, and 211 or less is most preferable. When _n2 is 246 or less, the line width of the mesh or the pitch of the mesh becomes a preferable size, making it difficult for radio waves to pass through. Further, in order to make the second region less noticeable, _n2 is preferably 150 or more, more preferably 173 or more, and even more preferably 190 or more.

Therefore, by setting the gradation value _n2 of the second region within the above range and setting the gradation difference index F within the above range, it is possible to provide the antenna unit 100 that is less noticeable and has improved antenna performance.

Further, a preferable range of (line width of mesh/pitch of mesh) x ₂ can be derived from the above equation (3). x ₂ is preferably 5.47×10 ⁻³ or more, more preferably 1.24×10 ⁻² or more, even more preferably 2.17×10 ⁻² or more, particularly preferably 3.91×10 ⁻² or more, The most preferable value is 4.61×10 ⁻² or more. Further, x ₂ is preferably 1.17×10 ⁻¹ or less, more preferably 9.02×10 ⁻² or less, and even more preferably 7.05×10 ⁻² or less. Therefore, by setting (mesh line width/mesh pitch) x ₂ within the preferable range and setting the shade difference index F within the above-mentioned range, the antenna unit 100 becomes less noticeable and improves antenna performance. can be provided.
The line width of the mesh may be 5 μm or more and 30 μm or less, and may be 6 μm or more and 15 μm or less. The mesh pitch may be 50 μm or more and 500 μm or less, and may be 100 μm or more and 300 μm or less.

In order to set the shade difference index F within the above range, n ₁ is preferably 246 or less, more preferably 240 or less, even more preferably 232 or less, particularly preferably 217 or less, and most preferably 211 or less. Further, n ₁ is preferably 150 or more, more preferably 173 or more, and even more preferably 190 or more.

Further, a preferable range of (dot diameter/dot pitch) x ₁ can be derived from the above equation (2). x ₁ is preferably 2.87×10 ⁻¹ or more, more preferably 3.10×10 ⁻¹ or more, even more preferably 3.41×10 ⁻¹ or more, particularly preferably 3.98×10 ⁻¹ or more, Most preferably, it is 4.21×10 ⁻¹ or more. Furthermore, x ₁ is preferably 6.54×10 ⁻¹ or less, more preferably 5.66×10 ⁻¹ or less, and even more preferably 5.01×10 ⁻¹ or less. Therefore, by setting (dot diameter/dot pitch) x ₁ within the preferable range and setting the gradation difference index F within the above range, it is possible to provide the antenna unit 100 that is less noticeable and has improved antenna performance. .
The diameter of the dots may be 50 μm or more and 500 μm or less.

As described above, according to the first embodiment, the pseudo layer 60 is arranged around the ground conductor layer 40, and by adjusting the difference in gradation value or color difference between the first region and the second region within a suitable range, An antenna unit and window glass with excellent design can be provided. Further, by adjusting the gradation value of the second region or the size of the dots of the first region within a suitable range, antenna performance can be suitably ensured.

Note that the first embodiment can also be modified as follows. For example, in the first embodiment described above, the pattern included in the pseudo layer 60 is a pattern in which the conductor array elements 61 are arranged at a predetermined pitch and spaced apart from each other, but the pattern is made of an insulator such as resin. It may be a pattern in which In this case, the pattern may be a pattern in which circular insulators are arranged spaced apart from each other at a predetermined pitch, a continuous pattern in which linear insulators are connected to each other, or a specific It may also be a mesh pattern. The shape of the pattern may be diamond, triangle, hexagon, star, or other shapes.

The pseudo layer 60 may be made of an insulator without containing a conductor. In this case, the pseudo layer 60 may be a solid planar insulator without a pattern.
Insulator materials include acrylic, polycarbonate, PVB (polyvinyl butyral), COP (cycloolefin polymer), PET (polyethylene terephthalate), polyimide, ceramics, or resins such as sapphire silicone resin, polysulfide resin, acrylic resin, Or glass etc. are mentioned. The pseudo layer 60 may be formed by printing ink (pigment) on these materials.

Furthermore, in the first embodiment, the ground conductor layer 40 has a mesh pattern, but the ground conductor layer 40 may be a solid planar conductor. In this case, the conductor material used for the ground conductor layer 40 may be a transparent material such as ITO (Indium Tin Oxide).

<Embodiment 2>
Next, a second embodiment of the present invention will be described. In the first embodiment, the pseudo layer 60 was on the same plane as the ground conductor layer 40 of the antenna unit 100. In the second embodiment, the pseudo layer 60 is on a different plane from the ground conductor layer 40.

[Configuration example 1]
FIG. 7 is a top view of the antenna unit 100A according to Configuration Example 1 of Embodiment 2. FIG. 8 is a plan view showing the radiating element layer 20, the ground conductor layer 40, and the pseudo layer 60A formed on the dielectric layer 10 of the antenna unit 100A according to the second embodiment.

The antenna unit 100A includes a dielectric layer 10, a radiating element layer 20, a pseudo layer 60A, and a ground conductor layer, as examples of the dielectric layer, first conductor layer, pseudo layer, and second conductor layer described in the overview. 40.

In Configuration Example 1, the radiation element layer 20 is provided on the first main surface 10(1) side of the dielectric layer 10 with the dielectric layer 10 as a reference.

In Configuration Example 1, the ground conductor layer 40 is a layer to be camouflaged, similar to Embodiment 1. The ground conductor layer 40 is provided on the second main surface 10(2) side of the dielectric layer 10 with respect to the dielectric layer 10.

In Configuration Example 1, similar to Embodiment 1, the pseudo layer 60A is a camouflage layer for making the ground conductor layer 40, which is the second conductor layer, less noticeable. Therefore, like the pseudo layer 60, the pseudo layer 60A is arranged around the ground conductor layer 40 in plan view. However, the pseudo layer 60A is different from the pseudo layer 60 in that the pseudo layer 60A is provided on the first main surface 10(1) side of the dielectric layer 10 with respect to the dielectric layer 10. More specifically, the pseudo layer 60A is formed on the same plane as the radiation element layer 20.

Note that in configuration example 1, the first region is an arbitrary region of the pseudo layer 60A, and the second region is an arbitrary region of the ground conductor layer 40. The preferred ranges of F, x ₂ , n ₂ and D are the same as in the first embodiment.

In configuration example 1, even if the pseudo layer 60A is not on the same plane as the ground conductor layer 40, the pseudo layer 60A is arranged around the ground conductor layer 40 in plan view, and the difference in gradation value between the first region and the second region is Alternatively, the same effects as in the first embodiment can be achieved by adjusting the color difference within a suitable range.

[Configuration example 2]
In configuration example 2, the pseudo layer 60A is a camouflage layer for making the radiating element layer 20 inconspicuous in place of making the ground conductor layer 40 inconspicuous. For example, if the conductor used for the ground conductor layer 40 is a transparent material such as ITO, and the conductor used for the radiating element layer 20 is an opaque material such as gold, silver, copper, etc., the radiating element layer 20 is likely to be noticeable. . However, this can be avoided by camouflaging the radiation element layer 20 with the pseudo layer 60A.

In Configuration Example 2, the arrangement of the radiation element layer 20, the ground conductor layer 40, and the pseudo layer 60A in the Z-axis direction is the same as in Configuration Example 1 of Embodiment 2. In other words, the radiating element layer 20 is formed on the first main surface 10(1) with the dielectric layer 10 as a reference, and the ground conductor layer 40 is formed on the second main surface 10(2) with the dielectric layer 10 as a reference. be done. However, the antenna unit 100A in configuration example 2 differs from configuration example 1 in that the radiating element layer 20 is the second conductor layer described in the outline, and the ground conductor layer 40 is the first conductor layer described in the outline.

In Configuration Example 2, the ground conductor layer 40 may have a continuous pattern, specifically a mesh pattern, similar to the ground conductor layer 40 of Embodiment 1, or may have a solid planar conductor.

Furthermore, in Configuration Example 2, the radiating element layer 20 may have a continuous pattern, specifically a mesh pattern, similarly to the ground conductor layer 40 of Embodiment 1.

In Configuration Example 2, the pseudo layer 60A is formed on the same plane as the radiation element layer 20.

FIG. 9 is a plan view showing the radiating element layer 20, the ground conductor layer 40, and the pseudo layer 60A formed on the dielectric layer 10 of the antenna unit 100A according to Configuration Example 2 of Embodiment 2. The pseudo layer 60A is arranged around the radiating element layer 20 in plan view. Specifically, it is arranged so as to be in contact with at least a portion of the outer edge of the radiation conductor 21 a included in the radiation element layer 20 and the outer edge of the power supply line 30 .

Note that in configuration example 2, the first region is an arbitrary region of the pseudo layer 60A, and the second region is an arbitrary region of the radiation element layer 20. The preferred ranges of F, x ₂ , n ₂ and D are the same as in the first embodiment.

Even if the object to be camouflaged is the radiating element layer 20, the pseudo layer 60A is arranged around the radiating element layer 20 in plan view, and the difference in tone value or color difference between the first region and the second region is kept within a suitable range. By adjusting this, you can achieve optimal camouflage. This improves the design.

[Configuration example 3]
From the viewpoint of manufacturing cost, the pseudo layer is formed on the same plane as the ground conductor layer 40 as in the first embodiment, or the pseudo layer is formed on the same plane as the radiating element layer 20 as in the second embodiment. It is preferable. Further, from the viewpoint of parallax, the pseudo layer is preferably formed on the same plane as the second conductor layer to be camouflaged. However, the pseudo layer may be formed on a plane different from both the radiating element layer 20 and the ground conductor layer 40.

For example, the antenna unit 100B has the same configuration as Configuration Example 1 or Configuration Example 2 in plan view, but the configuration in top view is different. FIG. 10 is a top view of an antenna unit 100B according to a third configuration example of the second embodiment. Antenna unit 100B differs from antenna unit 100A in that it includes a dielectric layer 11 and a pseudo layer 60B instead of pseudo layer 60A. Note that the antenna unit 100B includes a dielectric layer 10 in addition to the dielectric layer 11, and the dielectric layer described in the overview is the dielectric layer 10. Further, in the antenna unit 100B, the second conductor layer described in the overview may be the ground conductor layer 40 or the radiating element layer 20.

The dielectric layer 11 is a transparent plate-like, sheet-like, or film-like member through which visible light passes. Dielectric layer 11 functions as a support substrate for pseudo layer 60B. The dielectric layer 11 is provided on the negative side of the Z-axis with respect to the radiation element layer 20 so as to be parallel to the XY plane. As an example, the dielectric layer 11 is placed in contact with the radiating element layer 20. The rest of the description of the dielectric layer 11 is the same as that of the dielectric layer 10, so it will be omitted.

The pseudo layer 60B is provided on the negative Z-axis side with respect to the dielectric layer 11. As an example, the pseudo layer 60B is arranged on the surface of the dielectric layer 11 so that its surface is parallel to the XY plane. The shape and position of the pseudo layer 60B in plan view may be the same as the pseudo layer 60A of the first or second configuration example.

Note that in configuration example 3, the first region is an arbitrary region of the pseudo layer 60B, and the second region is an arbitrary region of the radiating element layer 20 or the ground conductor layer 40. The preferred ranges of F, x ₂ , n ₂ and D are the same as in the first embodiment.

Note that the dielectric layer 11 may be provided on the positive Z-axis side with respect to the ground conductor layer 40.
In this case, the pseudo layer 60B is provided on the positive Z-axis side with respect to the dielectric layer 11.

The pseudo layer 60B is arranged around the second conductor layer to be camouflaged in a plan view, and the difference in gradation value or color difference between the first region and the second region is adjusted within a suitable range. The same effects as in configuration example 1 or configuration example 2 are achieved.

<Embodiment 3>
Next, Embodiment 3 of the present invention will be described. There is a problem in that the reflection of radio waves at the interface of the window glass body 200 increases radiation toward the indoor side, resulting in a decrease in the FB ratio of the antenna unit. The indoor side is the Z-axis positive direction side. In order to solve this problem, an antenna unit is known in which a waveguide layer is provided on the outdoor side of the radiating element layer. The antenna unit according to the third embodiment corresponds to such an antenna unit. In the third embodiment, the object to be camouflaged is the waveguide layer in addition to the ground conductor layer.

FIG. 11 is a cross-sectional view of an antenna unit 100C according to the third embodiment. Specifically, FIG. 11 is a cross-sectional view taken along line XIV-XIV' of the antenna unit 100C shown in FIG. 12. FIG. 12 is a plan view of an antenna unit 100C according to the third embodiment. FIG. 13 is a plan view showing the radiation element layer 20C, the waveguide layer 80, and the pseudo layer 60C formed on the dielectric layer 12 according to the third embodiment. FIG. 13 shows a plan view of the dielectric layer 12 as seen from the first main surface side and a plan view of the dielectric layer 12 as seen from the second main surface side.

In the antenna unit 100C, the dielectric layer, first conductor layer, pseudo layer, and second conductor layer described in the overview are the dielectric layer 12, the radiating element layer 20C, the pseudo layer 60C, and the waveguide layer 80.

12 and 13 show, as an example, a configuration in which two antenna elements 20Ca and 20Cb are formed in the radiation element layer 20 shown in FIG. 11 (see the first main surface side in FIG. 13). Further, a configuration is shown in which two waveguide parts 80a and 80b are formed in the waveguide layer 80 shown in FIG. 11 (see the second main surface side in FIG. 13). Regarding the ground conductor layer 40, two ground conductors 40a and 40b are also formed. Note that the number of radiating elements, ground conductor layers, and waveguide sections included in the antenna unit 100C is not limited to two, and may be one, or may be three or more.

(Dielectric layer 12)
As shown in FIG. 11, the dielectric layer 12 is a transparent plate-like, sheet-like, or film-like member that transmits visible light. The dielectric layer 12 functions as a spacer to prevent the radiation element layer 20C and the waveguide layer 80 from coming into contact with each other. The main surface of the dielectric layer 12 is parallel to the XY plane, and the thickness direction is parallel to the Z-axis direction. The rest of the description of the dielectric layer 12 is the same as that of the dielectric layer 10, so it will be omitted.

Hereinafter, the main surface of the dielectric layer 12 in the positive Z-axis direction will be referred to as a first main surface 12(1), and the main surface of the dielectric layer 12 in the negative Z-axis direction will be referred to as a second main surface 12(2). . That is, the second main surface 12(2) is a main surface opposite to the first main surface 12(1).

(Radiating element layer 20C)
The radiating element layer 20C is a layer including a radiating conductor 21C formed to be able to transmit and receive radio waves in the target frequency band. The radiating element layer 20C, like the radiating element layer 20, is provided on the first main surface 10(1) side of the dielectric layer 10 with the dielectric layer 10 as a reference. Specifically, the radiation element layer 20C is formed on at least a portion of the first main surface 10(1) of the dielectric layer 10 so that its surface is parallel to the XY plane.

Further, in the third embodiment, the radiation element layer 20 is provided on the first main surface 12(1) side of the dielectric layer 12 with the dielectric layer 12 as a reference. Specifically, the radiation element layer 20C contacts at least a portion of the first main surface 12(1) of the dielectric layer 12 at the end face in the negative Z-axis direction.

As shown in FIGS. 12 and 13, antenna elements 20Ca and 20Cb basically have the same configuration and function as antenna elements 20a and 20b, but antenna elements 20Ca and 20Cb are rectangular planar conductors. Note that the shape of the antenna elements 20Ca and 20Cb is not limited to a rectangle, but may be a circle or any other arbitrary shape.

(Waveguide layer 80)
As shown in FIG. 11, the waveguide layer 80 has a function of guiding the radio waves radiated by the radiating element layer 20C in a predetermined direction. Specifically, the waveguide layer 80 has a function of guiding the radio waves emitted by the radiation element layer 20C toward the window glass body 200 to the outside. This improves the FB ratio.

The waveguide layer 80 is provided on the outdoor side with respect to the dielectric layer 12, that is, on the second main surface 12(2) side of the dielectric layer 12. Specifically, the waveguide layer 80 is formed on at least a portion of the second main surface 12(2) of the dielectric layer 12 so that its surface is parallel to the XY plane.

Examples of the material of the conductor used in the waveguide layer 80 include gold, silver, copper, platinum, aluminum, or chromium. The waveguide layer 80 may be formed by plating the above-mentioned material. By plating, it is possible to form a waveguide layer 80 that is resistant to corrosion and has a good design. Further, the waveguide layer 80 may be formed by sintering a pattern formed by screen printing a paste of silver, copper, or the like on the second main surface 12 (2).

The waveguide layer 80 may be formed directly on the second main surface 12(2), or may be formed indirectly. For example, the waveguide layer 80 may be formed on the second main surface 12(2) of the dielectric layer 12 via a resin layer. For the resin layer, for example, an interlayer film of polyvinyl butyral or ethylene vinyl acetate, polyethylene terephthalate, OCA, or the like can be used.

As shown in FIGS. 12 and 13, the waveguide section 80a included in the waveguide layer 80 includes conductor elements 81a, 82a, 83a, and 84a. Each of the conductor elements 81a, 82a, 83a, and 84a is a strip-shaped conductor element arranged parallel to and spaced apart from each other. In this example, conductor elements 81a, 82a, 83a, and 84a extend in the Y-axis direction. Further, in this example, the conductor elements 81a, 82a, 83a, and 84a are arranged in order from the negative direction of the X-axis, separated by a predetermined distance in the X-axis direction. In plan view, the distance between conductor element 82a and conductor element 83a is larger than the distance between conductor element 81a and conductor element 82a and the distance between conductor element 83a and conductor element 84a. Antenna element 20Ca is arranged between conductor element 82a and conductor element 83a in plan view.

Each of the conductor elements 81a, 82a, 83a, and 84a may be composed of a conductor pattern formed so as to create a gap in plan view, similarly to the linear ground conductor 41 of the ground conductor layer 40.
That is, each of the conductor elements 81a, 82a, 83a, and 84a is constituted by a continuous pattern in which linear conductors are electrically connected to each other, specifically, a mesh-like conductor pattern.

Note that the waveguide section 80b has the same configuration as the waveguide section 80a, so a description thereof will be omitted.

(pseudo layer 60C)
As shown in FIG. 11, the pseudo layer 60C is a camouflage layer for making the waveguide layer 80, which is the second conductor layer in the third embodiment, less noticeable. Similar to the waveguide layer 80, the pseudo layer 60C is provided on the second main surface 12(2) side of the dielectric layer 12 with the dielectric layer 12 as a reference. More specifically, the pseudo layer 60C is formed on the same plane as the waveguide layer 80. That is, the waveguide layer 80 is formed on at least a part of the second main surface 10(2) of the dielectric layer 10 so that its surface is parallel to the XY plane.

As shown in FIGS. 12 and 13, the pseudo layer 60C is arranged around the waveguide layer 80 in plan view. For example, the pseudo layer 60C may be placed so as to entirely surround each of the conductor elements 81a to 84a, or may be placed so as to be in contact with a portion of each of the conductive elements 81a to 84a. Further, the pseudo layer 60C does not need to be arranged between the adjacent conductor elements 81a and 82a, and between the adjacent conductor elements 83a and 84a.

Furthermore, the end of the pseudo layer 60C in the X-axis direction may coincide with the end of the dielectric layer 12 in the X-axis direction; They may be separated by just that. The same applies to the ends in the Y-axis direction.

By disposing the pseudo layer 60C around the waveguide layer 80 in a plan view in this way, the waveguide layer 80 can be camouflaged. This improves the design. Particularly remarkable effects are achieved when the antenna unit 100C has a plurality of waveguide sections 80a and 80b that are spaced apart from each other.

Here, the region A2 shown in FIGS. 12 and 13 is a region including the boundary between the pseudo layer 60C and the waveguide layer 80. Regarding area A2, in the description of area A1, the pseudo layer 60, the ground conductor layer 40, the first main surface 10(1), and the second main surface 10(2) are respectively replaced by the pseudo layer 60C, the waveguide layer 80, The explanations will be omitted by replacing them with the first principal surface 12(1) and the second principal surface 12(2). In other words, in the third embodiment, the first region is an arbitrary region of the pseudo layer 60C, the second region is an arbitrary region of the waveguide layer 80, and the specific configuration of the pattern of the waveguide layer 80 and the pseudo layer 60C , F, x ₂ , n ₂ and suitable ranges of D are the same as in the first embodiment.

The antenna unit 100C further includes a ground conductor layer 40 provided through the dielectric layer 10 on the opposite side of the dielectric layer 12 with respect to the radiating element layer 20C, and a pseudo layer 60 that camouflages the ground conductor layer 40. Be prepared. The configurations of the dielectric layer 10, the ground conductor layer 40, and the pseudo layer 60 are the same as in the first embodiment. The radiating element layer 20C is powered by a power feeding point (not shown) corresponding to a ground electrode (not shown) of the ground conductor layer 40.

According to the third embodiment, the pseudo layer 60C is provided around the waveguide layer 80 in a plan view, and the difference in gradation value or color difference between the first region and the second region is adjusted within a suitable range. Therefore, the waveguide layer 80 can be suitably made inconspicuous. Therefore, it is possible to provide an antenna unit and window glass with excellent design.

Note that the dielectric layer 12 between the waveguide layer 80 and the radiation element layer 20C may be a space instead of a transparent member. The medium of the space may be air or other gas, but the space may also be a vacuum. FIG. 14 shows an example of a case where the dielectric layer 12 is replaced with a space 12A. In this case, as shown in FIG. 14, the antenna unit 100C may include a dielectric layer 12B that supports the waveguide layer 80 on the Z-axis negative direction side with respect to the waveguide layer 80. The presence of the space 12A between the waveguide layer 80 and the radiation element layer 20C makes the resonance frequency less susceptible to the influence of the transparent member, improving the FB ratio. In addition, when the dielectric layer 12 is replaced with a space 12A and a dielectric layer 12B is provided that supports the waveguide layer 80 in the negative Z-axis direction with respect to the waveguide layer 80, as shown in FIG. A waveguide layer 80C may be further provided on the Z-axis negative direction side of the layer 12B. In this case, it may further include a pseudo layer 60D that camouflages the waveguide layer 80C.

<Embodiment 4>
Next, a fourth embodiment of the present invention will be described. In the third embodiment, the pseudo layer 60C was on the same plane as the waveguide layer 80 of the antenna unit 100C. However, the pseudo layer 60C may be on a different plane from the waveguide layer 80. Note that in the fourth embodiment, as in the third embodiment, the dielectric layer, first conductor layer, pseudo layer, and second conductor layer described in the overview are the dielectric layer 12, the radiation element layer 20C, and the pseudo layer 60C. , and a waveguide layer 80.

FIG. 15 is a top view of the antenna unit 100D according to the fourth embodiment. In the antenna unit 100D, the pseudo layer 60C is formed on a different plane from the radiating element layer 20 and the waveguide layer 80. For example, the antenna unit 100D further includes a dielectric layer 11 that functions as a support substrate for the pseudo layer 60C. The dielectric layer 11 is provided on the negative Z-axis side with respect to the waveguide layer 80 so as to be parallel to the XY plane. As an example, the dielectric layer 11 is placed in contact with the waveguide layer 80 . The other explanations of the dielectric layer 11 are the same as those of the dielectric layer 11 of the third configuration example of the second embodiment.

The pseudo layer 60C is provided on the negative Z-axis side with respect to the dielectric layer 11. As an example, the pseudo layer 60C is arranged on the surface of the dielectric layer 11 so that its surface is parallel to the XY plane. The shape and position of the pseudo layer 60C in plan view may be the same as the pseudo layer 60C of the third embodiment.

Note that in the fourth embodiment, the first region is an arbitrary region of the pseudo layer 60C, and the second region is an arbitrary region of the waveguide layer 80. The preferred ranges of F, x ₂ , n ₂ and D are the same as in the first embodiment.

Even when the pseudo layer 60C is placed on a plane different from the waveguide layer 80, it is arranged around the waveguide layer 80 in a plan view, and the difference in gradation value or color difference between the first region and the second region is preferably adjusted. By adjusting within this range, the same effects as in the third embodiment can be achieved.

<Embodiment 5>
Next, a fifth embodiment of the present invention will be described. Embodiment 5 is a modification of Embodiment 1. In the antenna unit 100 according to the first embodiment, the radiating element layer 20 and the ground conductor layer 40 were formed to face each other with the dielectric layer 10 in between. In the antenna unit according to the fifth embodiment, the radiating element layer and the ground conductor layer are formed on the same main surface side with the dielectric layer 10 as a reference.

FIG. 16 is a plan view of an antenna unit 100E according to the fifth embodiment. FIG. 17 is a cross-sectional view of an antenna unit 100E according to the fifth embodiment. Specifically, FIG. 17 is a cross-sectional view of the antenna unit 100E shown in FIG. 16 along the line XVII-XVII. FIG. 18 is a cross-sectional view of an antenna unit 100E according to the fifth embodiment. Specifically, FIG. 18 is a cross-sectional view of the antenna unit 100E shown in FIG. 16 along the line XVIII-XVIII.

In Embodiment 5, the dielectric layer, first conductor layer, pseudo layer, and second conductor layer described in the overview are the dielectric layer 10, the radiating element layer 20E, the ground conductor layer 40E, and the pseudo layer 60E.

The radiating element layer 20E, the ground conductor layer 40E, and the pseudo layer 60E have basically the same configuration and function as the radiating element layer 20, the ground conductor layer 40, and the pseudo layer 60, but are different in shape and arrangement. As shown in FIGS. 17 and 18, the radiating element layer 20E, the ground conductor layer 40E, and the pseudo layer 60E are all located on the first main surface 10(1) side of the dielectric layer 10 with respect to the dielectric layer 10. provided.
Specifically, as shown in FIG. 17, the radiating element layer 20E and the pseudo layer 60E are arranged on at least a portion of the first main surface 10(1) of the dielectric layer 10, with their surfaces parallel to the XY plane. It is formed to become. Further, as shown in FIG. 18, the ground conductor layer 40E is formed on at least a portion of the first main surface 10(1) of the dielectric layer 10 so that its surface is parallel to the XY plane. .

A cable 92 shown in FIG. 18 and the like is a member that electrically connects the radiation element layer 20E and the ground conductor layer 40E, and includes a conductive wire 91, an insulator 93, an outer conductor 94, and a sheath 95. In the cable 92, an insulator 93 covers a conductive wire 91, an outer conductor 94 covers the insulator 93, and a sheath 95 covers the outer conductor 94. As shown in FIG. 18, the cable 92 is arranged to bridge the radiating element layer 20E and the ground conductor layer 40E. Note that the outer conductor 94 of the cable 92 is exposed at a location adjacent to the ground conductor layer 40E, and is electrically connected by contacting or soldering to the ground conductor layer 40E. In the example shown in FIG. 18, the outer conductor 94 is electrically connected to the ground conductor layer 40E by solder 96. Further, the conductive wire 91 included in the cable 92 is exposed at a location adjacent to the radiating element layer 20E, and is electrically connected by contacting or soldering to the radiating element layer 20E. In the example shown in FIG. 18, conductive wire 91 is electrically connected to radiation element layer 20E by solder 97. In the example shown in FIG.

As shown in FIG. 16, the radiating element layer 20E is a rectangular planar conductor. Note that the shape of the radiation element layer 20E is not limited to this, and may be circular or any other arbitrary shape. The radiating element layer 20E is arranged in a portion of the dielectric layer 10 on the negative side of the Y-axis with respect to the center of the first main surface 10(1). The radiating element layer 20E includes a mesh-like conductor pattern.

The ground conductor layer 40E is a planar conductor pattern. The ground conductor layer 40E is arranged in a portion on the positive side of the Y-axis with respect to the center of the first principal surface 10(1) so as not to overlap with the radiating element layer 20E in a plan view. In this example, the end of the ground conductor layer 40E in the Y-axis positive direction coincides with the end of the first main surface 10(1) of the dielectric layer 10 in the Y-axis positive direction. 10(1) may be separated by a predetermined distance in the Y-axis negative direction from the end in the Y-axis positive direction.

Note that the conductor pattern of the ground conductor layer 40E is the same as that of the ground conductor layer 40, so a description thereof will be omitted.

The pseudo layer 60E is an example of the pseudo layer described above. The pseudo layer 60E is a camouflage layer for making the radiation element layer 20E, which is the first conductor layer, and the ground conductor layer 40E, which is the second conductor layer, less noticeable. The pseudo layer 60E is a planar layer. The pseudo layer 60E is arranged around the ground conductor layer 40 and the radiating element layer 20E in plan view. This makes it possible to make the radiating element layer 20E and the ground conductor layer 40E, which were conspicuous due to being spaced apart, less conspicuous.

Region A3 shown in FIG. 16 is a region including the boundary between pseudo layer 60E and ground conductor layer 40E. Further, a region A4 shown in FIG. 16 is a region including the boundary between the pseudo layer 60E and the radiation element layer 20E. Regarding region A3, in the description of region A1, pseudo layer 60 and ground conductor layer 40 are replaced with pseudo layer 60E and ground conductor layer 40E, respectively, and the explanation is omitted. Regarding the region A4, in the description of the region A1, the pseudo layer 60 and the ground conductor layer 40 are replaced with the pseudo layer 60E and the radiating element layer 20E, respectively, and the explanation is omitted. The specific configuration of the patterns of the waveguide layer 80 and the pseudo layer 60C, the preferable ranges of F, x ₂ , n ₂ and D, etc. are the same as in the first embodiment.

As described above, according to the fifth embodiment, even when the ground conductor layer and the radiating element layer are formed on the same main surface side, it is possible to provide an antenna unit and window glass with excellent design.

Note that the pseudo layer 60E may be a camouflage layer for making either the radiation element layer 20E, which is the first conductor layer, or the ground conductor layer 40E, which is the second conductor layer, less noticeable. In this case, the pseudo layer 60E is arranged around the layer to be camouflaged in plan view.

[Experiment example 1: Indicator F of the difference in shading and inconspicuousness]
The inventors conducted the following Experimental Example 1 in order to verify the influence of the above-mentioned index F of the difference in density between the first region and the second region on the inconspicuousness of the second region. . Examples 1 to 10 are examples, and Examples 11 to 13 are comparative examples. In Experimental Example 1 below, as an example of the gradation value, a gray scale gradation value in which the number N of gradations is 256 was used.

(sample)
A sheet with a mesh pattern (mesh pattern) measuring 500 mm long x 600 mm wide x 0.14 mm thick was used as a sample corresponding to the first region. The meshes of the samples of Examples 1 to 6, 11, and 12 were regular hexagons, the distance between the centers of adjacent regular hexagons was 274 μm, and the width of the mesh was 14 μm. The meshes of the samples of Examples 7 to 10 and 13 were regular hexagons, the distance between the centers of adjacent regular hexagons was 548 μm, and the width of the mesh was 14 μm. Further, a sheet having a dot pattern with a diameter of 70 μm to 120 μm and a pitch of 150 μm to 280 μm was used as a sample corresponding to the second region. Note that the dots were approximately circular. In each example, a sample corresponding to the first region was selected from a plurality of samples having different mesh patterns, and a sample corresponding to the second region was selected from a plurality of samples having different dot patterns.

(Measurement of gradation value)
First, each sample was photographed using iR-ADV C5235F manufactured by Canon Inc. as an optical reader to obtain photographed images. At this time, the reading resolution was set to 400 dpi. Next, using Microsoft Paint from Microsoft Corporation, the gradation values at three randomly selected locations in the photographed image were measured. Then, the average of the gradation values at three randomly selected locations was taken as the gradation value n ₁ of the first region or the gradation value n ₂ of the second region corresponding to the sample.

(Calculation of gradation difference index F)
The gradation value n ₁ of the first region and the gradation value n ₂ of the second region were substituted into the above-mentioned equation (1) to obtain the index F of the difference in gradation.

(Evaluation of inconspicuousness)
In each example, a sample corresponding to the first region and a sample corresponding to the second region were lined up, and the inconspicuousness of the sample corresponding to the second region was visually evaluated. The evaluation of inconspicuousness is a sensory evaluation. The inconspicuousness evaluation was conducted by multiple subjects. Then, in each experimental example, the proportion r of subjects who evaluated that the sample corresponding to the second region was not conspicuous among all subjects was calculated. The results are shown in Table 1.
≪Evaluation criteria for inconspicuousness≫
Excellent (◎): r is 50% or more.
Good (○): r is more than 0% and less than 50%.
Bad (x): r is 0%.

In Examples 1 to 6, the tone value n ₁ of the first region was 201, |n ₁ −n ₂ | was 28 or less, and F was 1.09×10 ⁻¹ or less. Further, in Examples 1 to 6, r was 2.70% or more, and the inconspicuousness was good or excellent. In particular, in Examples 4 to 6, |n ₁ -n ₂ | is 9 or less, F is 3.52×10 ^-2 or less, r is 58.11% or more, and the inconspicuousness is excellent. Ta.

On the other hand, in Examples 11 and 12, the tone value n ₁ of the first region was 201, |n ₁ -n ₂ | were 30 and 33, respectively, and F was 1.29×10 ⁻¹ and 1 It was .17×10 ⁻¹ . Furthermore, in Examples 11 and 12, r was 0 and the inconspicuousness was poor.

In Examples 7 to 10, the tone value n ₁ of the first region was 232, |n ₁ −n ₂ | was 12 or less, and F was 4.69×10 ⁻² or less. Further, in Examples 7 to 10, r was 13.51% or more, and the inconspicuousness was good or excellent. In particular, in Examples 9 and 10, |n ₁ -n ₂ | is 4 or less, F is 1.56×10 ^-2 or less, r is 72.97% or more, and the inconspicuousness is excellent. Ta.

On the other hand, in Example 13, the tone value n ₁ of the first region was 232, |n ₁ −n ₂ | was 15, and F was 5.86×10 ⁻² . Further, in this example 13, r was 0, and the inconspicuousness was poor.

According to Experimental Example 1 above, when the gradation value n ₁ of the first region is 201, F is preferably 0 or more and 1.09×10 ⁻¹ or less, more preferably 0 or more and 6.25×10 ⁻² or less. , more preferably 0 or more and 3.52×10 ⁻² or less, particularly preferably 0 or more and 1.56×10 ⁻² or less.
Further, when the gradation value n ₁ of the first region is 232, F is preferably 0 or more and 4.69×10 ⁻² or less, more preferably 0 or more and 1.56×10 ⁻² or less.

[Experimental example 2: Relationship between (dot diameter/dot pitch) and gradation value in the first region]
The inventors conducted Experimental Example 2 in order to find the relationship between the dimensions of the dot pattern in the first region and the gradation values.

(Preparation of sample)
Sixty-five samples having dot patterns with a diameter of 70 μm to 120 μm and a pitch of 150 μm to 280 μm were prepared. Note that the dots were approximately circular.

(Measurement of sample diameter/pitch)
Using an electron microscope ("Dino-Lite Edge AMR Polarizer" manufactured by Optoscience), the sample piece was observed in plan, and the diameter and pitch of three randomly selected dots were measured.

(Measurement of gradation value)
Using iR-ADV C5235F manufactured by Canon Inc. as an optical reader, each sample was photographed to obtain photographed images. At this time, the reading resolution was set to 400 dpi. Next, using Microsoft Paint from Microsoft Corporation, the gradation values at three randomly selected locations in the photographed image were measured. Then, the average of the gradation values at three randomly selected locations was taken as the gradation value of the sample.

(Evaluation results)
The evaluation results of Experimental Example 2 are shown in FIG. FIG. 19 is a diagram showing the relationship between (dot diameter/dot pitch) and gradation value. Assuming that (dot diameter/dot pitch) is x ₁ , the relationship between the diameter/pitch x ₁ and the gradation value n ₁ was expressed approximately linearly, as shown in FIG. 19 . When a regression line was determined, the above equation (2) was obtained as the regression line.
Note that the broken line shown in FIG. 19 represents a regression line of gradation value with respect to (dot diameter/dot pitch).

In this manner, the inventors have discovered that the tone value _n1 of the second region included in the pseudo layer can be expressed by the ratio of the dot diameter to the pitch.

[Experimental example 3: Relationship between (mesh line width/mesh pitch) and gradation value in the second region]
The inventors conducted Experimental Example 3 in order to find the relationship between the dimensions of the mesh pattern in the second region and the gradation values.

(Preparation of sample)
Ten samples having a mesh pattern with a line width of 10 μm to 28 μm and a pitch of 274 μm to 548 μm were prepared. Note that the shape of the mesh in the mesh pattern was hexagonal.

(Measurement of sample line width/pitch)
Using an electron microscope ("Dino-Lite Edge AMR Polarizer" manufactured by Optoscience), the sample piece was observed in plan, and the line width and pitch of the mesh at three randomly selected locations were measured.

(Measurement of gradation value)
As in Experimental Example 2, the gradation value of each sample was measured.

(Evaluation results)
The evaluation results of Experimental Example 3 are shown in FIG. FIG. 20 is a diagram showing the relationship between (line width of mesh/pitch of mesh) and gradation value. Assuming that (line width of mesh/pitch of mesh) is x ₂ , the relationship between (line width of mesh/pitch of mesh) x ₂ and gradation value n ₂ is approximately linear, as shown in FIG. Ta. When a regression line was determined, the above equation (3) was obtained as the regression line.
Note that the broken line shown in FIG. 20 represents a regression line of the gradation value with respect to (line width of mesh/pitch of mesh).

In this way, the inventors have discovered that the gradation value _n2 of the second region included in the second conductor layer can be expressed by the ratio of the mesh line width to the mesh pitch.

[Experiment example 4: Regarding gradation value and antenna performance]
The inventors evaluated the antenna performance for the gradation value n ₂ of the second region in order to find a preferable range of the gradation value n ₂ of the second region from the viewpoint of antenna performance. In Experimental Example 4, FB ratio (Front Back ratio) was used as the antenna performance.

(sample)
A sheet with a mesh pattern measuring 500 mm long x 600 mm wide x 0.14 mm thick was used as a sample. In each example, mesh patterned sheets with different gradation values _n2 were used as samples. The sample used in Example 14 of Experimental Example 4 was the same as the sample used in Example 1 of Experimental Example 1.

(Measurement of gradation value _n2 )
As in Experimental Example 2, the gradation value of each sample was measured.

(Calculation of (mesh line width/mesh pitch) x ₂ )
x ₂ was calculated from the measured n ₂ using equation (3).

(Measurement of antenna performance)
The FB ratio was calculated from the directivity measurement results using an anechoic chamber. The frequency condition was 4550MHz. The antenna performance was evaluated by classifying the measured values according to the following evaluation criteria. The results are shown in Table 2.
≪Antenna performance evaluation criteria≫
Good (○): The measured value of the FB ratio is 10 dB or more.
Acceptable (△): The measured value of the FB ratio is 8 dB or more and less than 10 dB.
Poor (×): The measured value of the FB ratio is less than 8 dB.

In Examples 14 and 15, (mesh line width/mesh pitch) x ₂ was 3.91×10 ⁻² or more, the gradation value n ₂ was 211 or more, and the FB ratio was 10 dB or more. Furthermore, in Examples 16 and 17, x ₂ was 1.24×10 ⁻² or more, the gradation value n ₂ was 232 or more, and the FB ratio was 8 dB or more.

On the other hand, in Example 18, x ₂ was 3.15×10 ⁻³ , n ₂ was 248, and the FB ratio was poor.

According to Experimental Example 4 above, x ₂ is preferably 5.47×10 ⁻³ or more, more preferably 1.24×10 ⁻² or more, even more preferably 2.17×10 ⁻² or more, and 3.91× It is particularly preferably 10 ^-2 or more, and most preferably 4.61×10 ^-2 or more. Further, n ₂ is preferably 246 or less, more preferably 240 or less, even more preferably 232 or less, particularly preferably 217 or less, and most preferably 211 or less. If _n2 is 246 or less, particularly 217 or less, the FB ratio will be 8 dB or more, and antenna performance can be ensured.

The present invention is not limited to the above embodiments, and can be modified as appropriate without departing from the spirit. For example, in a plan view, the pseudo layer is arranged so that the entirety thereof does not overlap with the second conductor layer, but a portion thereof may overlap with the second conductor layer.

This application claims priority based on Japanese Patent Application No. 2022-035030 filed on March 8, 2022, and the entire disclosure thereof is incorporated herein.

1 Window glass 10, 11, 12, 12B Dielectric layer 10 (1) First main surface 10 (2) Second main surface 11 (1) First main surface 11 (2) Second main surface 12 (1) 1 main surface 12 (2) 2nd main surface 12A space 20, 20C, 20E radiating element layer 21 radiating conductor 22, 23, 24, 25 patch conductor 30 power supply line 32, 33 end 36 branch point 40, 40E ground conductor layer 41 Linear ground conductor 50 Planar ground conductor 60, 60A, 60B, 60C, 60D, 60E Pseudo layer 61 Array element 70, 72 Homogenization pattern 80, 80C Waveguide layer 81, 82, 83, 84 Conductor element

91 Conductive wire 92 Cable 93 Insulator 94 Outer conductor 95 Sheath 96, 97 Solder 100, 100A, 100B, 100C, 100D, 100E Antenna unit 200 Window glass body 300 Support part A1, A2, A3, A4 Boundary area

Claims (14)

1. a dielectric layer through which visible light passes;
   a first conductor layer;
   a pseudo layer;
   a second conductor layer provided separately from the first conductor layer,
   The first conductor layer is provided on the first main surface side of the dielectric layer with respect to the dielectric layer,
   The second conductor layer is provided on a side of the first main surface of the dielectric layer or a second main surface opposite to the first main surface of the dielectric layer, with the dielectric layer as a reference,
   In plan view, at least a portion of the pseudo layer is arranged around the second conductor layer,
   In the planar view, each of a first region of the pseudo layer that does not overlap with the second conductor layer and a second region of the second conductor layer that does not overlap with the pseudo layer is determined at a resolution of 400 dpi. Assuming that the gradation values of N (N is a natural number) stages when read are n ₁ and n ₂ (n ₁ and n ₂ are integers of 0 or more),
   |n ₁ -n ₂ |/N≦1.09×10 ⁻¹ Antenna unit.
2. The antenna unit according to claim 1, wherein |n ₁ -n ₂ |/N≦6.25×10 ⁻² .
3. The antenna unit according to claim 1 or 2, wherein N=256 and _n2 ≦246.
4. The first conductor layer includes a radiation conductor,
   The second conductor layer includes a ground conductor,
   The antenna unit according to any one of claims 1 to 3, wherein the second conductor layer is provided on the second main surface side of the dielectric layer with respect to the dielectric layer.
5. The first conductor layer includes a radiation conductor,
   The second conductor layer includes a ground conductor,
   The antenna unit according to any one of claims 1 to 3, wherein the second conductor layer is provided on the first main surface side of the dielectric layer with respect to the dielectric layer.
6. The first conductor layer includes a ground conductor,
   The second conductor layer includes a radiating conductor,
   The antenna unit according to any one of claims 1 to 3, wherein the second conductor layer is provided on the second main surface side of the dielectric layer with respect to the dielectric layer.
7. The first conductor layer includes a radiation conductor,
   The second conductor layer includes a waveguide element that guides radio waves radiated by the radiation conductor in a predetermined direction,
   The second conductor layer is provided on the second main surface side of the dielectric layer with respect to the dielectric layer,
   The antenna unit according to any one of claims 1 to 3, further comprising a ground conductor layer provided on the opposite side of the dielectric layer with respect to the first conductor layer.
8. The antenna unit according to any one of claims 1 to 7, wherein the pseudo layer includes a pattern in which array elements are arranged spaced apart from each other.
9. The antenna unit according to claim 8, wherein the array element has a conductivity of 1×10 ⁶ (S/m) or more.
10. The shape of the array element is circular;
    The antenna unit according to claim 9, wherein the average diameter of the array element is λ ₀ /2 or less, where λ ₀ is the free space wavelength of radio waves transmitted and received by the antenna unit.
11. The shape of the array element is a rectangle,
    The antenna unit according to claim 9, wherein the length of the long side of the array element is λ ₀ /2 or less, where λ ₀ is the free space wavelength of radio waves transmitted and received by the antenna unit.
12. The pseudo layer is made of an insulator,
    The antenna unit according to any one of claims 1 to 7, wherein the insulator has a conductivity of less than 1×10 ⁶ (S/m).
13. The antenna unit according to any one of claims 1 to 12, wherein the second conductor layer includes a mesh conductor pattern.
14. A window glass comprising the antenna unit according to any one of claims 1 to 13.

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